Friday, May 4, 2012

How to turn on/off camera LED / flashlight in Android


How to turn on/off camera LED / flashlight in Android


In this tutorial, we show you how to turn on/off the phone camera led or flashlight in Android. See code snippets :
1. Turn on
 camera = Camera.open();
 Parameters p = camera.getParameters();
 p.setFlashMode(Parameters.FLASH_MODE_TORCH);
 camera.setParameters(p);
 camera.startPreview();
2. Turn off
 camera = Camera.open();
 Parameters p = camera.getParameters();
 p.setFlashMode(Parameters.FLASH_MODE_OFF);
 camera.setParameters(p);
 camera.stopPreview();
And, put following permission on AndroidManifest.xml.
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-feature android:name="android.hardware.camera" />
P.S This project is developed in Eclipse 3.7, and tested with Samsung Galaxy S2 (Android 2.3.3).

1. Android Layout

A button only.
File : res/layout/main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/relativeLayout1"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >
 
    <Button
        android:id="@+id/buttonFlashlight"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"
        android:text="Torch" />
 
</RelativeLayout>

2. Activity

Read the code, a button to turn on / off the flashlight, it should be self-explanatory.
package com.mkyong.android;
 
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.Camera.Parameters;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
 
public class FlashLightActivity extends Activity {
 
 //flag to detect flash is on or off
 private boolean isLighOn = false;
 
 private Camera camera;
 
 private Button button;
 
 @Override
 protected void onStop() {
  super.onStop();
 
  if (camera != null) {
   camera.release();
  }
 }
 
 @Override
 public void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.main);
 
  button = (Button) findViewById(R.id.buttonFlashlight);
 
  Context context = this;
  PackageManager pm = context.getPackageManager();
 
  // if device support camera?
  if (!pm.hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
   Log.e("err", "Device has no camera!");
   return;
  }
 
  camera = Camera.open();
  final Parameters p = camera.getParameters();
 
  button.setOnClickListener(new OnClickListener() {
 
   @Override
   public void onClick(View arg0) {
 
    if (isLighOn) {
 
     Log.i("info", "torch is turn off!");
 
     p.setFlashMode(Parameters.FLASH_MODE_OFF);
     camera.setParameters(p);
     camera.stopPreview();
     isLighOn = false;
 
    } else {
 
     Log.i("info", "torch is turn on!");
 
     p.setFlashMode(Parameters.FLASH_MODE_TORCH);
 
     camera.setParameters(p);
     camera.startPreview();
     isLighOn = true;
 
    }
 
   }
  });
 
 }
}


3. Android Permission

Assign CAMERA permission.
File : AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.mkyong.android"
    android:versionCode="1"
    android:versionName="1.0" >
 
    <uses-sdk android:minSdkVersion="10" />
 
    <uses-permission android:name="android.permission.CAMERA" />
    <uses-feature android:name="android.hardware.camera" />
 
    <application
        android:debuggable="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:label="@string/app_name"
            android:name=".FlashLightActivity" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
 
</manifest>

4. Demo

None, until i have 2nd hand phone to capture the current flashlight on my phone :)



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